A catheterization procedure involves the piercing of a vein or artery of a patient with a needle carrying a cannula—also called “catheter”—and subsequently sliding the cannula over the needle and into the punctured blood vessel. After the needle is removed from the catheter, a tube—such as an IV line—is connected to the cannula via a connector for supplying an intravenous fluid to the patient.
Most catheterization procedures are carried out on cutaneous veins to minimize the health risks associated with any invasive procedure. One of the most frequent complications in catheterization procedures stems from repeated movements of the cannula inside the vein as well as the friction of the cannula against the entry site. This results in repeated micro-trauma and maceration of skin edges. This, in turn, contributes to conditions such as sore veins, phlebitis, infection and hence pain for the patient. Trauma can also be caused by accidental pulling of the connector and/or the attached IV line. These direct traumata, as well as multiple micro-traumas, to cutaneous veins will eventually damage the cutaneous veins to the extent that they are rendered unsuited for such procedures and may eventually result in more invasive procedures being needed such as central venous catheterization.
Repeated displacement of cannulas and consequent traumata lead to a requirement for re-siting, often multiple times. This may have a serious impact in term of material cost (e.g. needles, cannula and dressings) as well as additional clinician's time and detrimental effects on patient well-being.
Furthermore, the cannula poses a risk of infection and the entry site needs to be effectively protected from bacteria migrating from its connector to the puncture site along the length of the cannula.
Dressings adapted for catheterization are exemplified in patent documents such as EP0284219B2; U.S. Pat. No. 5,282,791; U.S. Pat. No. 5,968,000 and U.S. Pat. No. 4,941,882. Typically, these dressings comprise a slit or an indentation extending inwardly from one edge of the dressing to a centrally positioned aperture which is sized and shaped to receive and accommodate the cannula's connector. The existence of such slits substantially compromise the peripheral integrity of the dressing, thus increasing the risk of infection. The presence of a slit extending to the periphery of the dressing further adversely affects the resistance provided by it against unwanted pulling or pushing movement of the cannula.
Therefore known dressings for securing a cannula in position on a patient suffer from several disadvantages.